I decided to change the moth-eaten radiator on my Sptifire 1500, in an attempt to lessen the overheating. But, when I removed the drain plug in the engine block, nothing drained out. As I found a good deal of crud in some of the hoses, I dont take that as a good sign!

Take the take the bottom rad hose off and the plug out the block, plus heater hoses as a start. Alternate a garden hose on each (rubber gloves this weather!) until everything seems to run freely/clear. A good prod may be required in the engine plug with some thin wire to get it started. The heater should be flushed back and forth in a similar way. I then chuck some holts speedflush in, top up with water and take for a good drive, longer than it says on the tin anyway. Then drain, refill, run, empty etc until happy all clear, fill with 50% antifreeze and good to go!

Clive Senior

Location-Brighton, East SussexFoxy is here, 1500od tax exempt Toledo. Now has the decent engine back in Slant 4 engine bolted in, sprint box and axle. Just needs fettling and will be on the road....Spitfire Zetec project is started work progressing slooooowly on the road!

Ditto the above. I had to renew a hose on the GT6 today, so took the opportunity for some backflushing. Got a good initial flow from the block hole, but a poke around there soon released some crud which would have otherwise hindered proper cooling.

Make sure you thoroughly flush out the hose that exits from the top of the heater valve. When I took mine off I found it absolutely full of a wierd kind of minerally green crystal jelly like substance. I don't know what it was or what caused it but it was blocking the entire pipe solid! The pic below looks is a 1cm long cross section of the hose and as you can see it's entirely blocked apart from where I poked a tiny screwdriver through it!

I was about to flush mine and clean out, etc. but then I thought. Hang on, it doesn't leak, it doesn't overheat (even in 35'c up some serious hills in Wales) and it doesn't freeze. Should I be messing with it? In the end, I figured any slodge in the rad was brobably blocking rad leaks so didn't bother!!

The trouble with doing nothing is that silt builds up in the radiator and heater matrix over time. If you flush it out regularly it dosen't get time to build up and solidify in such quantities as to cause a problem. If you leave it until you actually have a problem you may well find any chance to flush it out has gone and you're in new radiator territory!